Cartridge Pinout

To the best of my knowledge this is a complete cart pinout.

This table is originally from
David Tucker, and I've just added the recently found pins.

*Notes:

Pins 55-58 are analog sound pins
that the VB goes through between the sound source and the speakers. My
guess it that they would have been used in the future for an audio
enhancement chip, much like the Super Nintendo used.

Pins 10,12,14 are the last 3
addresses that were never used on the VB, but that means that the VB
supports up to a 128 mbit chip! That would be a nice multicart! ;-)

Pin 4 is /ES which is the
expansion area select, which was to be used in the future for addon
chips, similar to the SuperFX and other chips used on the SNES.

Pin 9 is /INTCRO, which is the
interrupt for the expansion area.

Pin 5 is /WE. When writing to a
memory location, this pin is pulled low (perfect for writing flash
in-system)

Pin 7 is connected to CS2 (active high chip select) on the cart SRAM,
but watching the pin on the oscilloscope, it doesn't appear to change
during SRAM access. It isn't physically connected directly to
+5V, so don't use it for power, and it shouldn't be connected to the
+5V bus, but I'd recommend not designing anything to use that pin without first verifying that it works the way you expect.